send a torrent to a friend(trackerless)but offline problem

[thai]

I created a torrent trackerless as below:

in the trackers I added:

http://my public IP:my port/announce

http://localhost:my port/announce

But ı couldn't send the file because ,I checked from utorrent and saw that

in the trackers tab for http://my public IP:my port/announce ,is offline(timeout)

.

only http://localhost:my port/announce is working.

After this error ,I activated DHT and recreated the torrent by adding

http://my public IP:my port/announce

http://localhost:my port/announce

again.

After this,I was able to send the torrent with DHT working.

But the problem is http://my public IP:my port/announce didn't work again.

Still the same problem as I described before.

I am a little bit confused.So is it useless to add trackers such as:

http://my public IP:my port/announce

http://localhost:my port/announce

Should I leave the trackers empty when creating torrent and only enabling DHT instead?

What is the difference between these two ways of creating torrent?

And why do I get this offline error?